what exactly does cast(shared) and cast away shared do?

[Kagamin]

On Tuesday, 16 June 2020 at 08:07:41 UTC, Simen Kjærås wrote:
> Correct. So it's perfectly possible to have a shared and a 
> non-shared reference to the same object, which is potentially 
> dangerous. A DIP* has been accepted that will limit your 
> ability to do dangerous things in this case, but it is not yet 
> implemented.
>
>
> * 
> https://github.com/dlang/DIPs/blob/master/DIPs/accepted/DIP1024.md

Uh, people already believe DIP1024 is an all purpose safety 
feature. Hello, it isn't. Especially it does nothing in case you 
have differently typed references to the same data.